After being on the bench for Chelsea's Champions League quarter-final exit to Manchester United on Tuesday, Drogba was restored to the starting line-up at The Hawthorns and proved almost unplayable.
The Blues went behind when Peter Odemwingie scored, but Drogba was on hand to restore parity before goals from Salomon Kalou and Frank Lampard secured the points for Ancelotti's side.
"As we know Didier had a problem with malaria and lost a few months when he was not 100%," said Ancelotti.
"But when he is, every time he is able to use his abilities, his power for the team, and he has a body that can continue for a long time.
"He has to continue to train well, be professional, because for a player who is 30 years old, it is important he trains, to have good control of his body, and do everything to maintain his fitness."
Source: PA
Source: PA